High pressure gas storage

ABSTRACT

A storage wellhead allowing on-line system maintenance and testing is provided. Including at least two fluidically parallel gas passages adapted to allow testing or maintenance of one gas passage, while the other gas passage remains in service. The gas may be hydrogen. Also including at least two fluidically parallel liquid passages adapted to allow testing or maintenance of one liquid passage, while the other liquid passage remains in service. The liquid may be brine.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/303,310 filed Jun. 12, 2014, the entire contents of which areincorporated herein by reference.

BACKGROUND

The storage of gases in very deep caverns, whether leached in saltformations or created by hard rock mining, or other gas storage at highpressure conditions require equipment rated for that pressure.Regulatory statues require periodic function testing of emergencycontrol valves and safety equipment. Commercial demand requirescontinuous flow of gas from the storage cavern, thus creating the needfor multiple flow paths from the storage cavern.

SUMMARY

A storage wellhead allowing on-line system maintenance and testing isprovided. Including at least two fluidically parallel gas passagesadapted to allow testing or maintenance of one gas passage, while theother gas passage remains in service.

The gas may be hydrogen. Also including at least two fluidicallyparallel liquid passages adapted to allow testing or maintenance of oneliquid passage, while the other liquid passage remains in service. Theliquid may be brine.

BRIEF DESCRIPTION OF THE FIGURES

For a further understanding of the nature and objects for the presentinvention, reference should be made to the following detaileddescription, taken in conjunction with the accompanying drawings, inwhich like elements are given the same or analogous reference numbersand wherein:

FIG. 1 illustrates one embodiment of the present invention.

FIG. 2 illustrates another embodiment of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

Illustrative embodiments of the invention are described below. While theinvention is susceptible to various modifications and alternative forms,specific embodiments thereof have been shown by way of example in thedrawings and are herein described in detail. It should be understood,however, that the description herein of specific embodiments is notintended to limit the invention to the particular forms disclosed, buton the contrary, the intention is to cover all modifications,equivalents, and alternatives falling within the spirit and scope of theinvention as defined by the appended claims.

It will of course be appreciated that in the development of any suchactual embodiment, numerous implementation-specific decisions must bemade to achieve the developer's specific goals, such as compliance withsystem-related and business-related constraints, which will vary fromone implementation to another. Moreover, it will be appreciated thatsuch a development effort might be complex and time-consuming, but wouldnevertheless be a routine undertaking for those of ordinary skill in theart having the benefit of this disclosure.

For the purpose of this invention, the definition of high pressure isdefined as a gas storage pressure at or above 2401 psig.

This invention claims the design of the storage wellhead for highpressure gas to include two outlets on both the gas and the liquidwellhead spools to facilitate testing and maintenance of valves so as tonot interrupt gas or liquid flow. For gas storage pressures of 2401 psigto 4000 psig, all flanges and valves meet API 5000 (API 5M) and for gasstorage pressures of 4001 psig to 8000 psig, all flanges and valves meetAPI 10000 (API 10M).

This invention further claims that the wellhead design includeshydraulically operated valves of the required pressure rating for use asemergency shutdown devices (ESDs) on the high pressure gas and brinesystems. The piping size of the hydraulically operated valves can befrom 2 inch up to 9 inch. The protection of brine and water systemswhich operate at lower pressure require an additional automatic valve inthe line to create a double block on the brine out of the storage well.All automated valves in this invention are designed to fail closed onloss of signal, loss of hydraulic pressure, and on loss of instrumentgas.

This invention further claims that the liquid master valve, highpressure gas wing valves, brine wing valves, and brine logging valvedesign includes the use of manual valves of the required pressurerating. The piping size of the manually operated valves can be from 2inch up to 9 inch.

This invention further claims that each wellhead spool has a flangeconnection for pressure indication.

Turning to FIGS. 1 and 2, a storage wellhead allowing on-line systemmaintenance and testing is described. Within a gas wellhead spool (117)is a gas passage (102) and a liquid passage (101). As the gas passage(102) penetrates the gas wellhead spool (117), it splits into at leasttwo fluidically parallel gas passages (103,104). The gas wellhead spool(117) is adapted to allow testing or maintenance of one gas passage(103,104), while the other gas passage remains in service.

The storage wellhead may be designed such that each gas passage (103,104) is capable of conveying the entire design gas flowrate. The gas maybe hydrogen. Each gas passage may comprise an automatic gas valve(107,108). Each gas passage (103, 104) may comprise a gas wing valve(105, 106). After passing through the gas passage (103, 104), the gaswing valve (105, 106), and the automatic gas valve (107, 108), the gasexits the storage wellhead through conduit (109), to be utilizeddownstream.

As illustrated in FIG. 1, during normal operation, which is to say undernon-testing conditions, all gas passages (103, 104), automatic gas valve(107, 108), and gas wing valves (105, 106) may remain in service. FIG. 2illustrates the situation where one automatic gas valve (107) is closed,as would be the case during testing, while simultaneously the otherautomatic gas valve (108) is open and allowing gas to pass.

As the liquid passage (101) penetrates the gas wellhead spool (117), itsplits into at least two fluidically parallel liquid passages (110,111),wherein the liquid wellhead spool (118) is adapted to allow testing ormaintenance of one liquid passage (110, 111), while the other liquidpassage remains in service. The storage wellhead may be designed suchthat each liquid passage (110, 111) is capable of conveying the entiredesign liquid flowrate. The liquid may be brine. Each liquid passage maycomprise an automatic liquid valve (114,115). Each liquid passage (110,111) may comprise a liquid wing valve (112, 113). After passing throughthe liquid passage (110, 111), the liquid wing valve (112, 113), and theautomatic liquid valve (114, 115), the liquid exits the storage wellheadthrough conduit (116), to be utilized downstream.

As illustrated in FIG. 1, during normal operation, which is to say undernon-testing conditions, all liquid passages (110, 111), automatic liquidvalve (114, 115), and liquid wing valves (112, 113) may remain inservice. FIG. 2 illustrates the situation where one automatic liquidvalve (115) is closed, as would be the case during testing, whilesimultaneously the other automatic gas valve (114) is open and allowinggas to pass.

The gas passage (103, 104), or automatic gas valve (107,108), testingmay occur at predefined first intervals. The predefined first intervalmay be once a month. The liquid passage (110,111), or automatic liquidvalve (114,115), testing may occur at predefined second intervals. Thepredefined second interval may be once a month.

The gas wellhead spool may operate at a pressure of greater than 2400psig. The gas wellhead spool may operate at a pressure of less than 4000psig. The gas wellhead spool may operate at a pressure of less than 3000psig.

All automatic gas valves (107,108) and all automatic liquid valves(114,115) may be tested at a predefined third interval. The predefinedthird interval may be every six months. The automated valves may behydraulically operated.

The test may comprise measuring the time for each valve to move from afully open position to a fully closed position.

The liquid wellhead spool may operate at a pressure of greater than 2400psig. The liquid wellhead spool may operate at a pressure of less than4000 psig. The liquid wellhead spool may operate at a pressure of lessthan 3000 psig.

It will be understood that many additional changes in the details,materials, steps and arrangement of parts, which have been hereindescribed in order to explain the nature of the invention, may be madeby those skilled in the art within the principle and scope of theinvention as expressed in the appended claims. Thus, the presentinvention is not intended to be limited to the specific embodiments inthe examples given above.

1-21. (canceled)
 22. A method of on-line system maintenance and testingof a storage wellhead, comprising a performing testing or maintenance ona first fluidically parallel and interchangeable hydrogen passage of ahydrogen wellhead spool passages each fluidically parallel andinterchangeable hydrogen passage comprising at least one automatichydrogen valve configured to fail close while a second fluidicallyparallel and interchangeable hydrogen passage of the hydrogen wellheadspool simultaneously remains in service, or a performing testing ormaintenance on a first fluidically parallel and interchangeable brinepassage of a brine wellhead spool each fluidically parallel andinterchangeable brine passage comprising at least one automatic brinevalve configured to fail close, while a second fluidically parallel andinterchangeable brine passage of the brine wellhead spool simultaneouslyremains in service.
 23. The method of claim 22, wherein each hydrogenpassage further comprises a hydrogen wing valve.
 24. The method of claim22, wherein each brine passage further comprises a brine wing valve. 25.The method of claim 22, wherein under non-testing conditions allautomated hydrogen valves remain open.
 26. The method of claim 22,wherein under non-testing conditions all automated brine valves remainopen.
 27. The method of claim 22, wherein the automated hydrogen valvetesting occurs at predefined first intervals.
 28. The method of claim27, wherein the predefined first interval is once a month.
 29. Themethod of claim 22, wherein the automated brine valve testing occurs atpredefined second intervals.
 30. The method of claim 29, wherein thepredefined second interval is once a month.
 31. The method of claim 22,wherein all automated hydrogen valves and all automated brine valves aretested at a predefined third interval.
 32. The method of claim 31,wherein the third interval is every six months.
 33. The method of claim32, wherein the test comprises measuring the time for each valve to movefrom a fully open position to a fully closed position.
 34. The method ofclaim 22 wherein the automated valves are hydraulically operated. 35.The method of claim 22, wherein the hydrogen wellhead spool operates ata pressure of greater than 2400 psig.
 36. The method of claim 35,wherein the hydrogen wellhead spool operates at a pressure of less than4000 psig.
 37. The method of claim 36, wherein the hydrogen wellheadspool operates at a pressure of less than 3000 psig.
 38. The method ofclaim 22, wherein the brine wellhead spool operates at a pressure ofgreater than 2400 psig.
 39. The method of claim 38, wherein the brinewellhead spool operates at a pressure of less than 4000 psig.
 40. Themethod of claim 39, wherein the brine wellhead spool operates at apressure of less than 3000 psig.